CAJ | 학술논문

对5A06防锈铝合金及其焊接接头疲劳性能断裂行为进行研究,采用疲劳试验、光学显微镜、扫描电子显微镜等手段对5A06铝合金的疲劳性能、金相组织、裂纹扩展特征和疲劳断口进行分析.结果表明:在循环次数为2×106时,铝合金母材、对接接头、横向十字、侧面连接和纵向十字接头的疲劳性能分别为99.97、70.96、57.48、48.20和41.80 MPa;铝合金母材疲劳裂纹起裂于截面最小部位,对接接头和横向十字接头裂纹起裂于焊趾等应力集中部位,裂纹沿着热影响区扩展;侧面连接接头裂纹起裂于两板连接处应力集中部位,纵向十字接头裂纹起裂于热影响区;微观裂纹为沿晶和穿晶混合的扩展特征.对母材及其焊接接头的宏观断口呈暗灰色纤维状,具有一定的塑性;接头的微观断口具有准解理特征,断口中存在球状孔洞、疲劳条纹和韧窝,并存在二次裂纹.
대5A06방수려합금급기한접접두피로성능단렬행위진행연구,채용피로시험、광학현미경、소묘전자현미경등수단대5A06려합금적피로성능、금상조직、렬문확전특정화피로단구진행분석.결과표명:재순배차수위2×106시,려합금모재、대접접두、횡향십자、측면련접화종향십자접두적피로성능분별위99.97、70.96、57.48、48.20화41.80 MPa;려합금모재피로렬문기렬우절면최소부위,대접접두화횡향십자접두렬문기렬우한지등응력집중부위,렬문연착열영향구확전;측면련접접두렬문기렬우량판련접처응력집중부위,종향십자접두렬문기렬우열영향구;미관렬문위연정화천정혼합적확전특정.대모재급기한접접두적굉관단구정암회색섬유상,구유일정적소성;접두적미관단구구유준해리특정,단구중존재구상공동、피로조문화인와,병존재이차렬문.
@@@@Fatigue testing fracture behavior was researched on 5A06 antirust aluminum alloy and its welded joints. The fatigue properties, microstructure, fatigue crack propagation character and fatigue fracture were investigated by fatigue test, optical microscopy (OM) and scanning electronic microscopy (SEM). Under cycle times of 2×106, the fatigue strengths of base metal (BM), butt joint (BJ), transverse cross joint (TJ), lateral connection joint (LJ) and longitudinal cross joint(LCJ) are 99.97, 70.96, 57.48, 48.20 and 41.80 MPa, respectively. The fatigue crack initiation site is in the smallest section for base metal, the crack initiation is in the weld toe and the crack propagates along the HAZ for the BJ and TJ, the crack initiation is in the fillet weld leg for the LJ, the crack initiation is in HAZ for the LCJ, the micro-crack propagates for transgranular and intergranular. The fatigue macro-fracture shows a dark gray fibrous fracture patterns and has some plasticity, the micro-fracture surface consists of quasi-cleavage patterns, spherical hole, fatigue striation and dimple, and numerous secondary cracks are observed.